Slip forming machines are usually used to build highways of a type which are constructed of concrete. One such device is shown in U.S. Pat. No. 4,073,592 to Godbersen, which is incorporated herein by reference.
These slip forming paver machines often have various stages of moving and smoothing concrete while inserting, reinforcing for dowel bars or the like. In the past, the concrete has not always been completely as smooth as possible or desirable, so the concrete would be manually smoothed to some extent.
Within the last decade or so, it has been common to put a trowel on the back end of a slip forming machine and to reciprocate it in one direction while moving it back and forth across the pavement in another direction. This device can be seen, for example, in United Kingdom Patent No. GB 2080374B which was patented in 1983, which patent is also incorporated herein by reference.
One of the problems associated with a finishing trowel of the automatic type is that it has been difficult to keep the lower surface thereof flat and smooth. If sheet metal is used for such a trowel which is heavy enough to keep it flat and smooth, it increases the cost of manufacture considerably and may be too heavy for proper concrete finishing under certain circumstances.
Furthermore, the prior art automatic finishing trowels have not been easily adjustable to apply the desired amount of pressure against the concrete being smoothed. The optimum pressure against the concrete being smooth varies to some extent, depending upon the conditions such as the wetness or dryness of the concrete.
Furthermore, the prior art automatic trowel members for slip forming machines often are difficult to balance and retain in a balanced fashion and when not balanced, they do not operate in an optimum fashion. Consequently, there is a need for an apparatus to assist in adjusting the balance for these devices.